The invention concerns a diagnostic test unit for analysing a body fluid in particular for blood sugar tests according to the preamble of claims 1 and 7.
Such test units can be used especially as consumables to determine blood sugar in automated hand-held devices which can be used even by laymen to carry out the necessary analytical steps in a simple and rapid manner. A plurality of test fields provided with a suitable test chemistry are arranged successively on the wound analytical tape. Alternatively individual test strips can also be removed from a magazine. The body fluid is applied to a test field provided in this manner in order to then enable a detection to be carried out locally by an optical analysis.
Various sealing concepts are described in WO 2004/056269 A1 of the applicant in order to protect the unused part of a test tape in a container against damaging environmental influences and at the same time allow the tape to be transported for the successive provision of the test fields. In this connection the test tape is dispensed over an aperture between the seal and a housing wall where the sealing elements are located on the profiled side of the test field whereas the rear wall is rigid. A separate filling means is provided for the assembly and filling.
EP-A-1321769 describes a dispensing apparatus for the use of test strips in which a single strip is provided by a translational movement through and between a seal and a rigid housing cover from a stored stack. A slide drawer is provided to fill it with a stack of strips which has to be separately sealed.
A disposable cassette unit is known from WO 2006/002432 A1 which comprises a housing, strip-shaped test sensors located therein, a dispensing mechanism and a movable seal. The so-called “duckbill seal” forms a projecting circumferential sealing lip which under slight deformation rests on both sides against the dispensed test strip. A problem in this connection is the inadequate contact pressing force which decreases even further as the period of use increases due to material fatigue. An adequate sealing function is not ensured especially in the case of different height profiles of the test material. A similar sealing design using sealing lips which loosely rest against one another is also known from WO 2006/059241 A2 for a tape containing electrochemical sensors.